Semiconductor devices containing integrated circuits (ICs) are used in a wide variety of electronic apparatus. The IC devices (or chips) comprise a miniaturized electronic circuit that has been manufactured in the surface of a substrate of semiconductor material. The circuits are composed of many overlapping layers, including layers containing dopants that can be diffused into the substrate (called diffusion layers) or ions that are implanted (implant layers) into the substrate. Other layers are conductors (polysilicon or metal layers) or connections between the conducting layers (via or contact layers).
IC devices can be fabricated in a layer-by-layer process that uses a combination of many steps, including imaging, deposition, etching, doping and cleaning. Silicon wafers are typically used as the substrate and photolithography is used to mark different areas of the substrate to be doped or to deposit and define polysilicon, insulators, or metal layers. One of the latter steps in the semiconductor fabrication process forms the electrical connections between the circuitry and the other electrical components in the electronic apparatus of which the IC chip is a part. While older technology utilized wire bonding, newer technology includes flip chip bonding processes where the active side of the IC chip is bonded to an electrical circuit of the printed circuit board (PCB) through solder bumps deposited either on the IC chip or the PCB.